Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

During rest and digest, which system would be active in the gastrointestinal tract?

1. Sympathetic nervous system

2. Parasympathetic nervous system

3. Central nervous system

4. Enteric nervous system

The correct answer is: Parasympathetic nervous system

The parasympathetic nervous system is primarily responsible for the body's "rest and digest" activities, which includes promoting digestive processes. During this state, the parasympathetic system enhances gastrointestinal function by increasing the mobility of the digestive organs, stimulating saliva production, enhancing gastric secretions, and promoting peristalsis in the intestines. This activation contributes to efficient digestion and absorption of nutrients, as well as maintenance of overall gastrointestinal health. The sympathetic nervous system, which is often activated during 'fight or flight' situations, tends to inhibit digestive activities. The central nervous system plays a broader role in relaying signals throughout the body but does not specifically control the 'rest and digest' function in isolation. The enteric nervous system, while it is integral to the gastrointestinal tract's autonomic functioning, largely operates independently and is influenced by both the sympathetic and parasympathetic systems. Thus, in the context of rest and digest activity, the correct system that is dominantly active in the gastrointestinal tract is the parasympathetic nervous system.